Water-soluble Ligand for Bioorthogonal Click Reactions

Tris(3-hydroxypropyltriazolylmethyl)amine (THPTA) is a water-soluble ligand, which is synthesized by the click reaction (= Hüisgen 1,3-dipolar cycloaddition reaction) using tripropargyl amine and 3-azido-1-propanol.¹⁾ In the presence of a copper ion, THPTA can be applied to Cu-catalyzed alkyne-azide cyclization (CuAAC), the typical bioorthogonal reaction with non-interferance in living systems. By forming a copper complex it will accelerate the CuAAC process.²⁾ Therefore, CuAAC using THPTA is applicable to not only the modification of hydrophilic polymers³⁾ and the bioconjugation of peptides containing an azido group,⁴⁾ but also the rapid labeling of metabolically-incorporated azido or alkyne tags on living cell surfaces.⁵⁾